Design of highly efficient and carbon-resistant catalysts for biogas reforming using entropy engineering strategy

Methane reforming yields syngas with H₂/CO ratios of 1 or 3, whereas the optimal ratio for methanol synthesis is 2. However, during long-term reforming, catalysts suffer deactivation from sintering and carbon deposition. Consequently, a general catalyst design principle tailored to industrial methanol synthesis is urgently needed. This study synthesized a high-entropy catalyst, NiLaMgAlCaCeO_x, via mechanochemical ball milling, employing entropy engineering for Gibbs free energy reduction. The reforming performance of this high-entropy catalyst was evaluated using simulated biogas. An H₂/CO ratio suitable for methanol production was achieved by adjusting H₂O addition, and performance was compared with control catalysts. XPS, SEM, TEM, H₂-TPD, TG, and FTIR techniques elucidated the high-entropy catalyst's anti-sintering and carbon deposition resistance mechanisms. Results indicated that the high-entropy oxide structure in NiLaMgAlCaCeO_x possesses high configurational entropy, which effectively restricts high-temperature active component migration and efficiently facilitates deposited carbon removal, preventing deactivation. This structure confers superior activity and stability compared to the control NiLaCeO_x. Specifically, its reforming stability under simulated biogas surpassed that of control catalysts NiLaMgAlCeO_x, NiLaMgCeO_x, and NiLaCeO_x. The key resistance against sintering and carbon deposition lies in high CO₂ and H₂O adsorption energy on the highentropy catalyst, coupled with multi-metal composition limiting Ni migration at elevated temperatures. This high-entropy stabilization mechanism, promoting resistance to sintering and mitigation of carbon deposition, offers valuable insights for future industrial methanol catalyst design.